Until now I've been using subdirectories in the main web directory for the various web projects - like http://localhost/projectone and http://localhost/projecttwo - or I simply renamed the main directory every time I switched project.
While that works, it is clunky and tedious and error-prone. And there are some things in webprogramming which does not work on 'localhost', like cookie validation. It also makes it impossible to have sitespecific sessions.
What I really want is http://one.projects and http://two.projects.
I've known about virtual hosts in Apache for some time, but I've kept putting it off because I thought it would be difficult. But it turned out to be simple enough. 